Anna Clark and Lia Clay were unlikely best friends in high school, but their yin-and-yang personalities drew them together in a sister-like bond. Then during college, Lia inexplicably walked out on their friendship and disappeared, leaving Anna hurt, confused, and disillusioned. Twenty years later, Anna discovers a letter Lia wrote the summer after high school-a letter that contains a cryptic postscript concealing a devastating truth. With her twenty-year high school reunion approaching, Anna moves closer to uncovering the secret in Lia's letter and the heartbreaking consequences it set in motion. As the layers of deceit and betrayal begin to unravel, Anna is forced to question everything she believes and come to terms with what it means to forgive the one person who hurt her in the worst way imaginable.